Relevant factors of depression in dementia modifiable by non-pharmacotherapy: a systematic review

Depression in dementia patients is associated with complications such as decreased activities of daily living and decreased quality of life. Because pharmacotherapeutic treatments for depression in dementia patients may have a poor risk-benefit ratio, effective non-pharmacotherapeutic interventions are favourable. However, the development of effective treatments requires the identification of depression-associated factors that can be modified by non-pharmacotherapeutic means in dementia patients. This systematic literature review aimed to identify modifiable factors related to depression and confirm that these factors can be improved by non-pharmacotherapeutic interventions. We searched PubMed, SpringerLink, the Web of Science, and the Cochrane Library for articles published between June 2007 and June 2017. We included studies that investigated causes of depression in dementia patients and excluded studies with unclear dementia diagnostic criteria or operational definitions. Of 9004 records screened, 6 studies were included. The participants included community-dwelling individuals and long-term care facility residents. The severity of dementia varied from mild to severe. After reviewing the studies, we identified five modifiable relevant factors in community-dwelling individuals: (i) pain; (ii) neuropsychiatric symptoms; (iii) cognitive decline; (iv) social isolation; and (v) quality of life. In long-term care facility residents, we identified neuropsychiatric symptoms and quality of life as relevant factors. Our results indicated that non-pharmacological interventions that improve these factors may improve symptoms of depression. A longitudinal study is recommended to clarify the mechanisms underlying depression symptoms and treatment in dementia patients. In addition, further investigation is needed to elucidate the ways in which differing dementia types and severity affect symptoms of depression.